Human placenta extract (PLx) possesses various physiologically important activities, such as antioxidant activity and anti-inflammatory activity. Therefore, purification and identification of the active antioxidants of PLx was attempted. Purification was performed successively by 40% methanol precipitation, Sephadex G-50 gel chromatography, and highperformance liquid chromatography (HPLC), and based on HPLC retention times, UV, NMR, and FAD-MS, the isolated components from PLX were identified as uracil, tyrosine, and phenylalanine. In order to confirm whether these compounds have similar function as PLx, effects of the administration of these compounds on the ethanol-induced liver injury of mice were examined. As a result, PLx suppressed ethanol-induced decrease in hepatic glutathione level, increase in thiobarbituric acid reaction substance (TBARS), increase in the activities of glutamate pyruvate transaminase, glutamate oxaloacetate transaminase, and superoxide dismutase, and decreas
… Moree in the activity of catalase. A mixture of uracil, tyrosine, and phenylalanine showed similar antioxidant activity to PLx, except for failure to suppress the increase in TBARS.Although these results suggest that PLx has some other unknown components to alleviate acute alcoholic liver injury, the mixture of uracil, tyrosine, and phenylalanine appeared to have almost the same ability to suppress acute ethanol-induced liver injury in mice as that of PLx.Next, in vivo antioxidative effects of curcumin were investigated using a trichloroethylene (TCE)-induced oxidative stress model in mouse liver. Increases in the contents of peroxisome and TBARS and decreases in GSH content of mouse liver by the TCE administration were suppressed by the pre-administration of curcumin. TCE-induced changes in the activities of antioxidative enzyme, such as Cu/Zn-SOD, catalase, glutathione reductase, glutathione peroxidase (GPX) and glucose-6-phosphate dehydrogenase (G6PD), were also diminished by curcumin. These results indicate that curcumin significantly suppresses TCE-induced oxidative stress by scavenging various free radicals, and its antioxidative activity seems to be derived from its suppressive effects on the increase in peroxisome content and decrease in GPx and G6PD activities. Less